* {
    padding: 0;
    margin: 0;
}

body {
    padding-top: 100px;
}

.main {
    width: 600px;
    height: 600px;
    margin: 0 auto;
    background-color: burlywood;
}

.col {
    position: relative;
    width: 40px;
    height: 40px;
    box-sizing: border-box;
    border: 1px solid #000;
    border-collapse: collapse;
    /*border-radius: 20px;*/
}

.row {
    position: relative;
    display: flex;
    height: 40px;
    /*background-color: brown;*/
}

.col-action {
    background-color: blue;
}

.col-actionA {
    /*background-color: white;*/
}

.col-actionB {
    /*background-color: black;*/
}

.col-actionA::before {
    content: "";
    position: absolute;
    width: 30px;
    height: 30px;
    background-color: white;
    border-radius: 99px;
    top: 4.5px;
    left: 4.5px;
    box-shadow: 0 0 2px rgba(0, 0, 0, 0.5);
}

.col-actionB::before {
    content: "";
    width: 30px;
    height: 30px;
    background-color: black;
    border-radius: 99px;
    position: absolute;
    top: 4.5px;
    left: 4.5px;
    box-shadow: 0 0 2px rgba(128, 128, 128, 0.5);
}

.hq {
    width: 600px;
    height: 600px;
    margin: 0 auto;
}